Filter element with percussion band

ABSTRACT

A filter element has a reinforcement band or ring along at least a portion of the perimeter thereof and performing a support function thereat preventing or minimizing damage upon attempted percussive cleaning of the filter element by service personnel striking the perimeter against an impact surface. Alternatively, a failure band or ring is provided along at least a portion of the perimeter and performs a designated failure function to a failure condition thereat upon attempted percussive cleaning, with the failure condition providing at least one of: a) an indication to service personnel that the filter element has been damaged and should not be re-installed; and b) a deformed condition preventing re-installation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.13/410,369, filed Mar. 2, 2012, which is a division of U.S. patentapplication Ser. No. 12/545,497, filed Aug. 21, 2009, now U.S. Pat. No.8,128,719 issued Mar. 16, 2012.

BACKGROUND AND SUMMARY

The invention relates to filter elements.

Filter elements for filtering fluid are known in the prior art includingannular filter elements (cylindrical, oval, elliptical, racetrackshaped, and other closed-loop shapes), and including panel filterelements. The filter element typically includes filter media having aborder or perimeter having a frame and/or seal therealong. An annularfilter element typically includes annular filter media having a hollowinterior and extending axially between first and second axial ends, withthe first axial end being open and defining an axial flow paththerethrough communicating with the hollow interior, and with fluidflowing axially along the axial flow path through the noted open axialend. A panel filter element is typically flat and may have a rectangularshaped perimeter. During servicing, it is not uncommon for servicepersonnel to remove the filter element from its housing and attempt topercussively clean same by striking the perimeter or border of thefilter element (e.g. one or both of the axial ends of an annular filterelement; e.g. the edge of the perimeter or border of a panel filterelement) against an impact surface, to dislodge and shake freecontainment and dirt. This can damage the filter element includingseals, which in turn can open a bypass flow path, defeating the filterfunction when the filter element is re-installed.

The present invention arose during continuing development efforts in theabove technology, including directed toward solving the noted problems.

BRIEF DESCRIPTION OF THE DRAWINGS Prior Art

FIGS. 1-14 are taken from U.S. Pat. No. 6,902,598, incorporated hereinby reference.

FIG. 1 is taken from FIG. 1 of the noted incorporated '598 patent.

FIG. 2 is taken from FIG. 2 of the '598 patent and is sectional viewtaken along line 2-2 of FIG. 1

FIG. 3 is taken from FIG. 3 of the '598 patent and shows the open axialend of a closed loop pleated media filter element prior to potting ofthe end cap.

FIG. 4 is taken from FIG. 4 of the '598 patent and shows the open axialend of the filter element of FIG. 3 after potting of the end cap.

FIG. 5 is taken from FIG. 5 of the '598 patent and is a view of a moldfor molding an end cap onto pleated filter media of a filter element.

FIG. 6 is taken from FIG. 6 of the '598 patent and is a view like aportion of FIG. 2 and shows an alternate embodiment.

FIG. 7 is taken from FIG. 7 of the '598 patent and is like FIG. 2 andshows the invention of the '598 patent.

FIG. 8 is taken from FIG. 8 of the '598 patent and is like FIG. 3 andshows the invention of the '598 patent.

FIG. 9 is taken from FIG. 9 of the '598 patent and is like FIG. 4 andshows the invention of the '598 patent.

FIG. 10 is taken from FIG. 10 of the '598 patent and is like FIG. 5 andshows the invention of the '598 patent.

FIG. 11 is taken from FIG. 11 of the '598 patent and is like FIG. 6 andshows the invention of the '598 patent.

FIG. 12 is taken from FIG. 12 of the '598 patent and is like FIG. 7 andshows a further embodiment.

FIG. 13 is taken from FIG. 13 of the '598 patent and is like FIG. 7 andshows a further embodiment.

FIG. 14 is taken from FIG. 14 of the '598 patent and is like FIG. 9 andshows a further embodiment.

Present Invention

FIG. 15 is like a portion of FIGS. 4 and 9 and shows the presentinvention.

FIG. 16 is like FIG. 15 and shows a further embodiment.

FIG. 17 is like a portion of FIGS. 2, 6, 7, 11, 12, 13 and shows thepresent invention.

FIG. 18 is an end view partially cutaway of the construction of FIG. 17.

FIG. 19 is like FIG. 15 and shows a further embodiment.

FIG. 20 is like FIG. 19 and shows a further embodiment.

FIG. 21 is like FIG. 20 and shows a further embodiment.

FIG. 22 is like FIG. 17 and shows a further embodiment.

FIG. 23 is an end view partially cutaway of the construction of FIG. 22.

FIG. 24 is like FIG. 16 and shows a further embodiment.

FIG. 25 is like FIG. 22 and shows a further embodiment.

FIG. 26 is a perspective view of a component for use in a filter elementin accordance with the invention.

FIG. 27 is a perspective view of a partially assembled filter includingthe component of FIG. 26.

FIG. 28 is like FIG. 26 and shows a further embodiment.

FIG. 29 is a perspective view partially cutaway of a filter elementincorporating the component of FIG. 28.

FIG. 30 is a like FIG. 25 and shows a further embodiment.

FIG. 31 is an end view partially cutaway of the construction of FIG. 30.

FIG. 32 is a perspective view showing a further embodiment.

FIG. 33 is an enlarged view of a portion of FIG. 32.

FIG. 34 is a perspective view showing a further embodiment.

DETAILED DESCRIPTION Prior Art

The following description of FIGS. 1-14 is taken from incorporated U.S.Pat. No. 6,902,598. The '598 patent incorporates U.S. Pat. Nos.6,149,700, 6,261,334, 6,391,076, 6,398,832, which are also allincorporated herein by reference.

FIGS. 1 and 2 show a filter 20 including a filter element 22 containedwithin a housing 24. Filter element 22 is provided by pleated filtermedia 26, FIG. 2, having a plurality of pleats 28, FIGS. 3, 4, in aclosed loop, typically an annulus, having an outer perimeter 30 definedby a plurality of outer pleat tips 32, and an inner perimeter 34 definedby a plurality of inner pleat tips 36. The annular closed loop has ahollow interior 38 extending along an axis 40. Housing 24 is typicallycylindrical and is provided by housing sections 42 and 44 mounted toeach other in conventional manner such as by overcenter spring clip typeclamps such as 46, or in other suitable manner. The housing has an inlet50 admitting inlet fluid, such as air or liquid, radially and/ortangentially into annular space 52 within the housing around filterelement 22. Alternatively, the inlet may be at an axial end of thehousing, for example as in incorporated U.S. Pat. No. 6,391,076. Thehousing may include an interior dam or deflection surface 54 forblocking direct impact against filter element 22 and/or for directingflow, for example in a spiral or toroidal pattern. The fluid flowslaterally or radially inwardly through filter media 26 into hollowinterior 38, and then the clean fluid flows axially rightwardly in FIG.2 in hollow interior 38 along flow passage 56 as shown at arrows 58, 59.Alternatively or additionally, the fluid may flow axially through thefilter media as in the noted incorporated '076 patent.

Flow passage 56 extending along axis 40 circumscribes hollow interior 38and has a flow perimeter 60 greater than inner perimeter 34 defined byinner pleat tips 36, as described in the incorporated '700 patent. Flowperimeter 60 is less than outer perimeter 30 defined by outer pleat tips32. Inner perimeter 34 defines and bounds a first cross-sectional area.Flow perimeter 60 defines and bounds a second cross-sectional area. Thesecond cross-sectional area is greater than the first cross-sectionalarea. Outer perimeter 30 defines and bounds a third cross-sectionalarea. The second cross-sectional area is less than the thirdcross-sectional area. Filter element 22 has first and second axial ends62 and 64. Axial end 62 is open and provides axial flow passage 56therethrough. An end cap 66 of soft resilient compressible material,such as foamed potted urethane, axially abuts the axial ends 68 of thepleats. End cap 66 has an inner perimeter 70 greater than innerperimeter 34 defined by inner pleat tips 36. End cap 66 partially coversthe axial ends 68 of the pleats such that the laterally outward portions72 of the axial ends 68 of the pleats 28 are covered by end cap 66 butnot the laterally inward portions 74 of the axial ends 68 of the pleats,such that the laterally inward portions 74 of the axial ends of thepleats are uncovered and exposed at axial end 62 of filter element 22,FIG. 4.

In one embodiment, second axial end 64 of filter element 22 is closed. Asecond end cap 76, FIG. 2, of soft compressible resilient material, suchas foamed potted urethane, is provided at second end 64 of filterelement 22 and completely covers the axial ends 78 of the pleatsincluding the outer pleat tips 32 and the inner pleat tips 36 at axialend 64. End cap 76 also includes a central section 80 spanning andcompletely covering hollow interior 38 of filter element 22 at axial end64 of the filter element. Housing section 44 includes an annularinterior sidewall 82 extending partially axially into the housing tolocate and retain filter element 22 at axial end 64. In otherembodiments, central section 80 of end cap 76 is omitted, and a portionof housing 44 extends into hollow interior 38 of filter element 22 toclose axial end 64 of the filter element and to position axial end 64 ofthe filter element within the housing. Further embodiments are shown inthe noted incorporated '076 patent. End cap 76 includes an annular ridge84 engaging axial end wall 85 of housing section 44 and slightly axiallycompressed thereagainst to further aid in retention of filter element 22within the housing and to accommodate axial tolerances. End cap 66 alsoincludes an annular ridge 86 engaging axial end wall 88 of housingsection 42 and slightly radially compressed thereagainst to aid inretaining filter element 22 within the housing and to accommodate axialtolerances and also to provide an axial seal to prevent bypass of dirtyair from annular chamber 52 around axial end 62 of the filter element.Axial end wall 88 of housing section 42 has an outlet flow tube 90extending therethrough. In addition to or alternatively to the axialseal at 86, end cap 66 provides a radial seal at 70 against outlet flowtube 90.

End cap 66 has a sidewall 92 extending axially away from axial ends 68of pleats 28 at axial end 62 of filter element 22. The sidewall has thenoted inner perimeter 70, and has an outer perimeter 94. As noted above,inner perimeter 70 of sidewall 92 is greater than inner perimeter 34 offilter element 22 defined by inner pleat tips 36. Inner perimeter 70 ofsidewall 92 of end cap 66 is less than outer perimeter 30 of filterelement 22 defined by outer pleat tips 32. Outer perimeter 94 ofsidewall 92 of end cap 66 is greater than outer perimeter 30 of filterelement 22 defined by outer pleat tips 32. Flow tube 90 has an innersection 96 axially facing the axial ends 68 of pleats 28. Inner section96 of flow tube 90 has an inner perimeter 98 and an outer perimeter 100.Outer perimeter 100 is greater than inner perimeter 70 of sidewall 92 ofend cap 66, such that as filter element 22 at end cap 66 is axially slidrightwardly over inner section 96 of flow tube 90, end cap 66 isradially compressed to expand inner perimeter 70 along outer sidewall100 of flow tube inner section 96 to effect the noted radial seal. Innerperimeter 70 of end cap 66 is preferably stepped, as shown at 71 in FIG.8 of the noted incorporated '700 patent, to have slightly progressivelydecreasing diameters from right to left as viewed therein, to receiveand guide inner section 96 of flow tube 90 therealong and increaseradial sealing pressure. End cap 66 circumscribes inner section 96 offlow tube 90 and bears radially thereagainst at 70 in sealing relationto form the noted radial seal thereat. End wall 88 of housing section 42axially faces axial ends 68 of pleats 28, and end cap 66 also bearsaxially against end wall 88 in sealing relation at 86 to form the notedaxial seal thereat.

An outer liner 102, FIG. 2, provided by an expanded wire mesh or screenor perforated metal or plastic, circumscribes filter element 22 alongouter pleat tips 32 and has an axial end section 104 extending axiallybeyond the axial ends 68 of pleats 28. An inner liner may also beprovided at inner perimeter 34 along inner pleat tips 36. As abovedescribed, flow tube 90 communicates with hollow interior 38 of thefilter element along flow passage 56 and extends axially from the axialend of the filter element. End cap 66 at the axial end of the filterelement bears radially between and is radially compressed between andagainst section 104 of outer liner 102 and inner section 96 of flow tube90. Outer liner 102 extends axially at 104 into end cap 66 and is pottedtherein during the molding process, as described in the incorporated'700 patent. As noted above, sidewall 92 of end cap 66 extends axiallyaway from the axial ends 68 of pleats 28 at the axial end of the filterelement. Outer perimeter 94 of the end cap sidewall circumscribes outerliner section 104. The filter element may also include an inner liner103, FIG. 5, along inner pleat tips 36.

Pleats 28 have pairs of walls defining axially extending interiorchannels 106, FIG. 3, and also as shown in FIG. 7 of the incorporated'700 patent, and axially extending exterior channels 108. The walls ofthe pleats defining the exterior channels 108 are sealed to each othernear axial end 62 of the filter element by heat seal bonding along gluestrips, also known as hot melt, such as 110, and as shown in theincorporated '700 patent at FIGS. 4-6, 9, and for example as disclosedin U.S. Pat. No. 5,106,397, incorporated herein by reference. Thisprevents bypass of dirty air around the axial ends of the pleats atinner exposed portions 74. Fluid such as air flowing radially inwardlythrough the filter media as shown at 112, and as shown in theincorporated '700 patent at FIG. 4, or alternatively flowing axially asshown in the incorporated '076 patent at FIGS. 15, 16 thereof, must flowthrough the sidewalls of pleats 28 before such fluid can flow axiallythrough hollow interior 40 as shown at arrow 58 or axially through theinward portions 74 of the axial ends 68 of the pleats as shown at arrow59. Some of such air can flow axially rightwardly as shown at arrow 59axially along interior channels 106, and the balance of the aircontinues radially inwardly as shown at arrow 114, and as shown in theincorporated '700 patent in FIG. 4, and then flows axially as shown atarrow 58. The axial ends of exterior channels 108 at the axial end ofthe filter element are blocked by the noted hot melt seal bonding alongadhesive strips 110. Fluid flowing through the filter element is forcedto pass from exterior channels 108 to interior channels 106. FIGS. 6 and9 of the incorporated '700 patent show the seal bonded adhesive 110extending in exterior channels 108 all the way from inner pleat tips 36to outer pleat tips 32 as idealized. If the seal bond does not extendall the way from inner pleat tip 36 to outer pleat tip 32, then theshape of the interior channel 106 at outer pleat tip 32 will generallybe more rounded and the walls of pleats 28 forming exterior channels 108at outer pleat tips 32 will usually be closer together. In analternative, the adhesive seal bond in exterior channels 108 may extendfrom inner pleat tips 36 only partially towards outer pleat tips 32, andthe outer portions of exterior channels 108 are blocked at the axial endof the filter element at end cap 66. During the molding potting process,the liquid castable material into which the pleated filter media isdipped will foam up a short distance axially into the channels betweenthe pleats, as shown in the incorporated '700 patent at inner section116 in FIGS. 4, 8, 9 thereof, of the end cap which has migrated adistance 118, FIG. 4 of the incorporated '700 patent, between thepleats. The spacing of glue strips 110 on the pleats from the axial ends68 of the pleats may be adjusted as desired in standard glue seal stripapplicator machines. Preferably, glue seal strips 110 are spaced fromaxial ends 68 of the pleats by a small distance 118 to enable a slightdeformation of the axial ends 68 of the pleats by a dam in the moldduring the molding potting process, to keep the liquid castable materialof the end cap from flowing radially inwardly into inner portions 74 ofthe pleat ends which are desired to be exposed, which molding processand dam are disclosed in the noted '700 patent, and noted hereinafter.Alternatively, seal glue strips 110 may be applied at axial ends 68 ofthe pleats, without gap 118 therebetween.

FIG. 5 shows a mold 120 for molding or potting end cap 66 onto pleatedfilter media 26 of the filter element. The mold has a trough 122extending along an annular first perimeter and holding liquid castablematerial, such as urethane, therein into which axial ends 68 of pleats28 are dipped. The mold has an insert 124 with an upstanding dam 126extending along a second annular perimeter circumscribed by the notedannular perimeter of trough 122. Dam 126 engages axial ends 68 of thepleats between outer pleat tips 32 and inner pleat tips 36 and impedesflow of liquid castable material laterally radially inwardly towardsinner pleat tips 36. Trough 122 partially spans axial ends 68 of thepleats such that the laterally outward portions 72 of the axial ends ofthe pleats are covered by liquid castable material but not the laterallyinward portions 74 of the pleats, such that laterally outward portions72 of the axial ends 68 of the pleats are covered by end cap 66, and thelaterally inward portions 74 of the axial ends 68 of the pleats areuncovered by end cap 66 and are left exposed. It is preferred that thepleated filter media be dipped into the liquid castable material in themold by lowering the pleated filter media downwardly until axial ends 68of the pleats are engaged by dam 126, and then pushing the pleatedfilter media further slightly downwardly against the dam such that thedam slightly deforms axial ends 68 of the pleats at such engagementpoint which in turn pushes the pleat sidewalls forming the notedchannels slightly laterally to further block the channels and furtherimpede flow of liquid castable material laterally inwardly towards innerpleat tips 36. Trough 122 is bounded by an outer perimeter 126 and aninner perimeter 128. Outer perimeter 126 of trough 122 is greater thanouter perimeter 30 of the filter element defined by outer pleat tips 32.Inner perimeter 128 of trough 122 is less than outer perimeter 30 of thefilter element. Inner perimeter 128 of trough 122 is greater than innerperimeter 34 of the filter element defined by inner pleat tips 36. Thenoted second perimeter of the mold at annular dam 126 is less than orequal to inner perimeter 128 of trough 122.

As noted, the method for molding end cap 66 onto pleated filter media 26involves dipping axial ends 68 of the pleats into liquid castablematerial in trough 122 of mold 120, and engaging axial ends 68 of thepleats against dam 126 at a location between outer pleat tips 32 andinner pleat tips 36 such that dam 126 impedes flow of the liquidcastable material laterally inwardly towards inner pleat tips 36. Trough122 is provided and aligned such that it partially spans axial ends 68of the pleats such that the laterally outward portions 72 of the axialends of the pleats are covered by the liquid castable material duringdipping, but not the laterally inward portions 74 of the axial ends ofthe pleats. Further in accordance with the described method, laterallyinward flow of the liquid castable material is impeded along the axialends of the pleats toward inner pleat tips 36 by providing and aligningdam 126 to engage axial ends 68 of the pleats between outer pleat tips32 and inner pleat tips 36 such that laterally outward portions 72 ofthe axial ends of the pleats are covered by end cap 66, and laterallyinward portions 74 of the axial ends of the pleats are uncovered by endcap 66 and are left exposed. Trough 122 and filter element 22 arealigned during the noted dipping such that outer perimeter 126 of trough122 circumscribes outer perimeter 30 of the filter element defined byouter pleat tips 32, and inner perimeter 128 of trough 122 circumscribesinner perimeter 26 of the filter element defined by inner pleat tips 36.

FIG. 6 shows an alternate embodiment wherein outlet flow tube 90 a hasan outer section 90 b of reduced diameter to accommodate enginecompartment size and location requirements, yet maintaining an increaseddiameter inner section 90 c maintaining the increased diameter andperimeter flow passage 56 including axial fluid flow at 58 and the extraaxial fluid flow at 59, FIGS. 2 and 6. The spacing of axial end wall 88of housing section 42 from axial ends 68 of the filter media pleatsprovides a plenum 130 accommodating the extra flow and reducingrestriction.

The described filter construction was developed for air filters, thoughmay be used for other fluids such as liquid. In the disclosedembodiment, fluid to be filtered flows laterally inwardly through thefilter media from the outer perimeter to the inner perimeter and thenflows axially in the hollow interior, such that flow passage 56 is anoutlet flow passage. Alternatively, fluid to be filtered may flowaxially in hollow interior 38 and then flow laterally outwardly throughthe filter media from the inner perimeter to the outer perimeter, inwhich case flow passage 56 is the inlet flow passage. In anotheralternative, fluid flow to or from axial end 64 of the filter elementand through the media may be axial or a combination of axial and radial,for example as in the noted incorporated '076 patent. In otheralternatives, metal end caps are used instead of urethane end caps, orvarious combinations of materials are used for the end caps. In furtheralternatives, outer section 90 b, FIG. 7, of the flow tube has a largerinner diameter than inner section 90 c.

During further development, it has been found that there are someapplications where enhanced structural integrity is desired in the endcap area at 66, for example wet conditions, heavy load conditions,vibration, and the like. There are also circumstances where costreduction is desired. There are also circumstances where even furthersealing is desired.

FIGS. 7-11 are like FIGS. 2-6, respectively, and use like referencesnumerals where appropriate to facilitate understanding. Filter element22 is provided by pleated filter media 26 having a plurality of pleats28 in a closed loop having an outer perimeter 30 defined by a pluralityof outer pleat tips 32, and an inner perimeter 34 defined by a pluralityof inner pleat tips 36, and having a hollow interior 38 extending alongaxis 40. Fluid flows axially in hollow interior 38 as shown at arrow 58.The filter element has first and second axial ends 62 and 64. The firstaxial end is open and provides an axial flow passage 57 therethroughalong axis 40 communicating with hollow interior 38. A resilientlycompressible end cap 200 at the open axial end covers inner and outerpleat tips 36 and 32 and spans radially along axial ends 68 of thepleats between inner and outer perimeters 34 and 30. A flow tube 202communicates with hollow interior 38 and extends along axial flowpassage 57 and engages end cap 200. Flow tube 202 at engagement 204 withend cap 200 has an inner perimeter 206 greater than inner perimeter 34defined by inner pleat tips 36. Inner perimeter 206 of flow tube 202 atengagement 204 with end cap 200 is less than outer perimeter 30 definedby outer pleat tips 32.

End cap 200 has a first section 208 extending radially inwardly fromouter perimeter 30 defined by outer pleat tips 32, and has a secondsection 210 extending radially outwardly from inner perimeter 34 definedby inner pleat tips 36. First and second sections 208 and 210 meet at ajunction defining a step at 204 facing radially inwardly toward andengaging flow tube 202. The step at 204 has a first axial length. Flowtube 202 has an inner tubular portion 212 extending axially along step204. Tubular portion 212 has an inner axial end 214 facing the firstaxial end of the filter element at axial ends 68 of the pleats andseparated therefrom by section 210 of end cap 200. Flow tube 202 has aflange portion 216 extending radially from tubular portion 212 andfacing the first axial end of the filter element at axial ends 68 of thepleats and axially spaced from inner axial end 214 of tubular portion212 by a second axial length which is less than the noted first axiallength, to thus provide axial compression of end cap 200 including ataxial seal region 218. End cap 200 has a first axial thickness at firstsection 208 at outer perimeter 30, a second axial thickness at firstsection 208 at step 204, a third axial thickness at second section 210at step 204, and a fourth axial thickness at second section 210 at innerperimeter 34. The noted second axial thickness is greater than the notedthird axial thickness. The noted first axial thickness is greater thanthe noted fourth axial thickness. The noted first axial thickness isless than the noted second axial thickness. The noted third and fourthaxial thicknesses are substantially the same.

In one embodiment, the filter element includes in combination the notedsecond end cap 76 at the second axial end 64 of the filter element ataxial ends 78 of the pleats and covering inner and outer pleat tips 36and 32 and spanning radially between inner and outer perimeters 34 and30, and also spanning hollow interior 38 and closing the second axialend of the filter element. The filter element is preferably contained inthe noted housing having an end wall 220 facing the first axial end ofthe filter element. Flow tube 202 is part of end wall 220.

Flow tube 202 engages end cap 200 at first, second and third engagementseals 218, 222 and 224, respectively, to provide triple sealing of endcap 200 to flow tube 202. Seals 218 and 224 are axial seals, and seal222 is a radial seal. First inner portion 212 of flow tube 202 extendsaxially along step 204 and engages the step to form the noted secondradial seal 222. Tubular portion 212 has the noted inner axial end 214axially engaging end cap 200 at the noted second section 210 and formingthe noted third axial seal 224. Flow tube 202 has the noted flangeportion 216 extending radially from tubular 212 and axially spacedoutwardly of inner axial end 214 and axially engaging end cap 200 atfirst section 208 and providing the noted first axial seal 218. Secondradial seal 222 is axially between first and third axial seals 218 and224.

FIG. 10 shows a mold 120 for molding or potting end cap 200 onto pleatedfilter media 26 of the filter element. The mold has a trough 122 asabove. The mold has an insert 230 similar to insert 124 but withupstanding darn 232 at inner pleat tips 36 at inner perimeter 34.

FIG. 11 shows an alternate embodiment wherein outlet flow tube 202 a hasan outer section 201 a of reduced diameter to accommodate enginecompartment size and location requirements, yet maintaining an increasedinner diameter section 203 a, as in FIG. 6. The spacing of axial endwall 220 of the housing from axial ends 68 of the filter media pleatsprovides the noted plenum 130. End cap 200 a has the noted first andsecond sections 208 a and 210 a. End cap 200 a covers the inner andouter pleat tips 36 and 32 and spans radially between the inner andouter perimeters 34 and 30. The end cap provides the noted triplesealing at axial seals 218 a and 224 a and at radial seal 222 a.

As shown in comparing FIGS. 3, 4, 8, 9, the present construction sealsthe axial ends 68 of the pleats solely with urethane end cap 200, or 200a, and eliminates reliance upon hot melt 110 for sealing purposes. Thiseliminates the adhesive component in the design of FIGS. 3, 4, andsimplifies the production process, reducing cost. In the presentconstruction of FIGS. 8, 9, the axial ends 68 of the pleats 28 aresealed with the same urethane 200, or 200 a, used to pot the element,rather than a combination of hot melt 110 and urethane 66 as in FIGS. 3,4. The present construction also eliminates reliance upon the interfacebetween the glue 110, the filter media of the pleats 28, and theurethane 66 to prevent contaminants from passing to the clean side ofthe filter. The present construction further facilitates concentricityof the closed loop configuration. The present construction furtherenhances structural integrity, particularly in wet conditions, heavyload conditions, and vibration conditions.

FIG. 12 shows a further embodiment and uses like reference numerals fromabove where appropriate to facilitate understanding. End cap 200 b hasfirst section 240 extending radially inwardly from the outer perimeter30 defined by outer pleat tips 32, and has a second section 242extending radially inwardly from first section 240. First and secondsections 240 and 242 meet at a junction defining a step 204 b. Flow tube202 b communicates with hollow interior 38 and extends along axial flowpassage 57. Flow tube 202 b has an inner tubular portion 212 b extendingalong step 204 b and radially engaging the step to form a radial seal222 therewith. Flow tube 202 b has the noted flange portion 216extending radially outwardly from tubular portion 212 b and axiallyspaced from first axial end 68 of the filter element by first section240 of end cap 200 b therebetween. Flange portion 216 engages firstsection 240 of end cap 200 b at engagement point 218 b to form an axialseal therewith. Tubular portion 212 b has an inner axial end 244 axiallyfacing first end 68 of the filter element. Second section 242 of end cap200 b is axially between inner axial end 244 of tubular portion 212 band first axial end 68 of the filter element. Second section 242 of endcap 200 b extends radially inwardly from first section 240 of the endcap all the way to inner perimeter 34 defined by inner pleat tips 36.End cap 200 b covers inner and outer pleat tips 36 and 32 and spansradially between inner and outer perimeters 34 and 30. Inner axial end244 of tubular portion 212 b is axially spaced from second section 242of end cap 200 b by an axial gap 246 therebetween. This may be desiredin some applications to protect against excessive axial compression oraxial crushing. For example, it may be desired to protect the pleat endsat 68 from the line of axial force otherwise provided by the annulus atinner end 244 of the flow tube, with or without adhesive or hot melt 110between the pleats.

FIG. 13 shows a further embodiment and uses like reference numerals fromabove where appropriate to facilitate understanding. End cap 200 c has afirst section 250 extending radially inwardly from the outer perimeter30 defined by outer pleat tips 32, and has a second section 252extending radially inwardly from first section 250. First and secondsections 250 and 252 meet at a junction defining a step 204 c. Flow tube202 c communicates with hollow interior 38 and extends along axial flowpassage 57. Flow tube 202 c has a tubular portion 212 c extendingaxially along step 204 c and radially engaging the step to form a radialseal therewith. Flow tube 202 c has flange portion 216 extendingradially outwardly from tubular portion 212 c and axially spaced fromfirst axial end 68 of the filter element by the first section 250 of endcap 200 c therebetween. Flange portion 216 axially engages first section250 of end cap 200 c at engagement point 218 c to form an axial sealtherewith. Tubular portion 212 c has inner axial end 214 axially facingfirst end 68 of the filter element. Second section 252 of end cap 200 cis axially between inner axial end 214 of tubular portion 212 c andfirst end 68 of the filter element. Second section 252 of end cap 200 cextends radially inwardly from first section 250 only partially towardsinner perimeter 34 defined by inner pleat tips 36 and does not coverinner pleat tips 36. This embodiment may be desirable in instances wherethe additional migration or flow at 59 is desired. This embodiment mayalso be desirable where additional flow of potting material into thepleat ends and between the wall segments of the pleats is desired. Forexample, the wider the radial extent of the end cap along axial end 68of the filter element, the greater the axially leftward migration of themolten potting material into and between the pleats. This may bedesirable for enhanced sealing including greater interface area with theadhesive or hot melt 110 between the pleats. Inner axial end 214 oftubular portion 212 c may axially engage second section 252 of end cap200 c as shown in FIG. 13 to form a second axial seal 224 therewith asin FIG. 7. Alternatively, inner axial end 214 may be spaced axiallyrightwardly of second section 252 of the end cap by an axial gaptherebetween as at axial gap 246 in FIG. 12.

FIG. 14 shows a further embodiment including a filter element 260including a closed loop filter media member 262 having a hollow interior264 extending along a given axis 266, and which may also include anouter prefilter member 268 such as open cell foam. Fluid flows axiallyin hollow interior 264. The filter element has first and second axialends 270 and 271. First axial end 270 is open and provides an axial flowpassage 272 therethrough along axis 266 communicating with hollowinterior 264. A resiliently compressible end cap 274 is provided atfirst axial end 270. A flow tube as shown in dashed line at 276 andwhich is comparable to flow tube 202, communicates with hollow interior264 and extends along axial flow passage 272. Flow tube 276 has atubular portion 278, comparable to tubular portion 212, engaging end cap274 and forming a seal therewith, comparable to seal 218 and/or 222and/or 224. Tubular portion 278 is cylindrical. Filter media member 262is non-cylindrical. In one embodiment, the filter media member iselliptical, such as oval, racetrack shaped, or the like. End cap 274 hasa first section 280 extending radially inwardly from an outer perimeter282, and has second section 284 extending radially inwardly from firstsection 280 to an inner perimeter 286. First and second sections 280 and284 are comparable to first and second sections 240 and 242 and to firstand second sections 250 and 252. First and second sections 280 and 284meet at a junction defining a step 288, comparable to steps 204, 204 b,204 c. First section 280 has the noted outer perimeter 282, and has aninner perimeter 290 at step 288. Second section 284 has an outerperimeter 292 at step 288, and has the noted inner perimeter 286communicating with hollow interior 264. Outer perimeter 282 of firstsection 280 is non-cylindrical. Inner perimeter 290 of first section 280is cylindrical. Step 288 is cylindrical. Outer perimeter 292 of secondsection 284 is cylindrical. Cylindrical tubular portion 278 engages endcap 274 at cylindrical step 288, comparable to the above notedengagement of cylindrical portions 212, 212 b, 212 c with steps 204, 204b, 204 c. Inner perimeter 286 of second section 284 is non-cylindrical.Filter media member 262 and outer perimeter 282 of first section 280 ofend cap 274 are elliptical and have a radially extending major axis(left-right in FIG. 14), and a radially extending minor axis (up/down inFIG. 14). The radial extension of first section 280 of end cap 274 alongthe major axis between outer perimeter 282 of first section 280 of endcap 274 and step 290 is greater than the radial extension of firstsection 280 of end cap 274 along the minor axis between outer perimeter282 of first section 280 of end cap 274 and step 288. The radialextension of second section 284 of end cap 274 along the minor axisbetween step 288 and inner perimeter 286 of second section 284 of endcap 274 is greater than the radial extension of the second section 284of end cap 274 along the major axis between step 288 and inner perimeter286 of second section 284 of end cap 274. In the embodiment shown,filter media member 262 is provided by pleated filter media having aplurality of pleats as above in a closed loop having an outer perimeterdefined by a plurality of outer pleat tips, comparable to pleat tips 32,and an inner perimeter defined by a plurality of inner pleat tips,comparable to pleat tips 36, the loop having the noted hollow interior264 extending along the noted given axis 266. Other types of filtermedia may be used, including non-pleated media. The disclosed ellipticalfilter design may be used in implementations where it is desired to havean elliptical filter and to maximize the inlet or outlet diameter of thefilter or match specifications requiring cylindrical inlet or outletflow tubes.

Present Invention

FIGS. 15-31 use like reference numerals from above where appropriate tofacilitate understanding.

FIG. 15 shows filter element 22 of FIGS. 1, 2, modified, to bedescribed, for filtering fluid, including annular filter media 26 havinga hollow interior 38, FIGS. 2, 15, and extending axially along axis 40between first and second axial ends 62, 64, the first axial end 62 beingopen and defining an axial flow path 57, FIG. 7, therethroughcommunicating with hollow interior 38, the fluid flowing axially asshown at 58 along the axial flow path 57 through open axial end 62. Areinforcement ring 302, FIG. 15, is provided at least one of the notedaxial ends, e.g. at open axial end 62, and performs a support functionthereat upon attempted percussive cleaning of filter element 22 byservice personnel striking the axial end against an impact surface, forexample as schematically shown at 304. Annular filter media 26 has anouter circumference 30 and an inner circumference 34 and extendsradially therebetween. As used herein, annular includes circular,elliptical, oval, racetrack-shaped, and other closed-loop shapes. Firstaxial end 62 has an axially facing end face 68 extending radiallybetween inner and outer circumferences 34 and 30. Reinforcement ring 302is at least one of outer circumference 30, end face 68, and innercircumference 34, to be described. In various embodiments, to bedescribed, the reinforcement ring is an annular member at the outercircumference and/or at the end face and/or at the inner circumferenceand/or at the junction of the end face and the outer circumferenceand/or at the junction of the end face and the inner circumference. Thereinforcement ring may have various cross-sectional shapes such asrectangular or square as shown at 302 in FIG. 15, round as shown at 306in FIG. 16, as well as other cross-sectional shapes.

End cap 200, FIG. 15, may extend at section 210 radially inwardly allthe way to inner circumference 34, as in FIGS. 7, 11, 12, or may stopshort thereof as in FIGS. 2, 6, 13 at end cap 66. The end cap is amolded member, as described above, and encapsulates the junction of endface 68 and outer circumference 30 and extends radially inwardly alongend face 68 at least partially towards inner circumference 34.Reinforcement ring 302 is encapsulated in end cap 200. In oneembodiment, the reinforcement ring, or at least a portion thereof, is atend face 68 and spaced radially outwardly of inner circumference 34.

In FIG. 17, reinforcement ring 306 is an L-shaped member having a firstleg 308 along outer circumference 30 and a second leg 310 extendingradially inwardly, which leg 310 may extend all the way to innercircumference 34 as shown in FIG. 17, or may stop short thereof. Leg 310may be perforated as shown at perforations 312 in FIG. 18, which may bedesirable in those embodiments where the end cap does not extendradially inwardly all the way to or past inner circumference 34, whichembodiments provide the noted additional flow at 59, FIGS. 2, 6, 13.

Filter element 22 may have an outer liner, for example as shown at 102in FIGS. 2, 7, 11-13, which outer liner 102 extends axially along outercircumference 30 and may extend beyond end face 68 as shown at 104. InFIG. 19, outer liner 102 has a reinforcement segment 314 turned radiallyaway from outer circumference 30 and providing the noted reinforcementring. Reinforcement segment 314 is turned radially inwardly toward innercircumference 34. In FIG. 19, the reinforcement segment 314 is curled ina spiral as shown at 316. In FIG. 20, reinforcement segment 318 isturned radially inwardly toward inner circumference 34 and has aturn-back portion 320 turned back axially toward end face 68. In FIG.21, reinforcement segment 322 extends from a turn 324 at outercircumference 30 and extends radially inwardly to a termination end 326pointing toward inner circumference 34. In an alternative, reinforcementsegment 322 may extend radially inwardly all the way to innercircumference 34 as shown in FIG. 17, preferably with end capencapsulation thereof. In FIGS. 21 and 17, the reinforcement segment inone embodiment extends from a substantially 90° turn 324 at outercircumference 30 then substantially rectilinearly to termination end326. The reinforcement segment may be permeable as shown at 312 in FIG.18. In FIG. 22, the reinforcement ring 330 includes an outer axialsegment 332 along outer circumference 30, a radial segment 334 extendingradially inwardly from outer circumference 30 to inner circumference 34,and an inner axial segment 336 extending axially along innercircumference 34. Reinforcement ring 330 may be a separate member or maybe an extension of outer liner 102. In a further embodiment,reinforcement ring 330 may be an extension of inner liner 338. In afurther embodiment, reinforcement ring 330 at radial extension segment334, whether provided by a separate member or by an extension of outerliner 102 or by an extension of inner liner 338, may be perforated asshown at perforations 340, FIG. 23, which may be desirable if end cap200 is not extended radially inwardly all the way to inner circumference34, for example as shown at end cap 66 in FIGS. 2, 6, 13.

FIG. 24 shows a mold 342 for molding or potting end cap 200, or end cap66, FIG. 2, onto pleated filter media 26 of the filter element,comparable to mold 120, FIG. 5. End cap 200 at the noted first axial end68 has an axial extension portion 344 extending axially along outercircumference 30 including outer liner 102 if provided. Reinforcementring 346 is at axial extension portion 344 of the end cap. Axialextension portion 344 extends axially to an axial termination end 348.Reinforcement ring 346 is at termination end 348. Reinforcement ring 346is axially spaced from end face 68 in a given axial direction away fromaxial end 62. The end cap provides a seal formed by molding material atfirst axial end 62, as above noted. Reinforcement ring 346 is a damblocking flow of molding material therepast in the noted given axialdirection.

In FIG. 25, end cap 200 has an axial extension portion 352 extendingaxially along outer circumference 30 including outer liner 102 ifprovided, and has a radial extension portion 354 extending radiallyinwardly along end face 68. Reinforcement ring 356 is provided along theexterior of end cap 200. Reinforcement ring 356 has an axial segment 358extending axially along the exterior of axial extension portion 352 ofthe end cap and spaced radially outwardly of outer circumference 30 bythe axial extension 352 of the end cap therebetween. Reinforcement ring356 has a radial segment 360 extending radially along the exterior ofradial extension portion 354 of the end cap and spaced axially outwardlyof end face 68 by radial extension portion 354 of the end captherebetween.

In FIGS. 26, 27, the reinforcement ring is an annular ring member 362having a plurality of spokes 364 extending radially inwardly therefromto a central hub 366 axially aligned with hollow interior 38. The spokesat least partially cross end face 68. FIG. 27 shows a housing section368 comparable to housing section 42, FIGS. 1, 2, having an inlet 370comparable to inlet 50, and having an outlet 372 comparable to outlet90.

In FIGS. 28, 29, reinforcement ring 374 is provided by concentric firstand second ring members 376 and 378 at end face 68 and a structuralsupport web comprising a plurality of truncated spokes 380 extendingradially between the first and second ring members. Second ring member378 is at outer circumference 30, and first ring member 376 is spacedradially inwardly thereof. In the embodiment of FIGS. 28, 29 first ringmember 376 is at inner circumference 34, and reinforcement ring 374includes a third ring member 382 radially intermediate first and secondring members 376 and 378. Third ring member 382 has an axial extension384 extending axially away from end face 68 and axially beyond first andsecond ring members 376 and 378. In one embodiment, end cap 66encapsulates second and third ring members 382 and 378 and the junctionof outer circumference 30 and end face 68. Further in such embodiment,end cap 66 does not encapsulate first ring member 376, and fluid flowsaxially along axis 40 between structural support web truncated spokes380 at a location along end face 68 between first ring member 376 andend cap 66 as shown at arrow 59, which additional flow is also shown at59 in FIGS. 2, 6, 13.

In FIGS. 30, 31, the reinforcement ring is replaced by a failure ring386 at the noted open axial end 62. Failure ring 386 performs adesignated failure function to a failure condition at the open axial endupon attempted percussive cleaning of filter element 22 by servicepersonnel striking open axial end 62 against an impact surface 304, withthe failure condition providing at least one of: a) an indication toservice personnel that filter element 22 has been damaged and should notbe re-installed; and b) a deformed condition preventing re-installation.Failure ring 386 is at least one of outer circumference 30, end face 68and inner circumference 34. In one embodiment, the failure condition isselected from the group consisting of fracture, tearing, failure,protruding, re-assembly prevention, and change in shape. In theembodiment of FIGS. 30, 31, failure ring 386 is an annular fracture disk388 at end face 68 and spanning from outer circumference 30 at leastpartially radially inwardly toward inner circumference 34 and having aplurality of tapered radial slots 390, FIG. 31, tapering to wider widthsas the slot extends radially inwardly toward inner circumference 34. Inanother embodiment, the noted indication is selected from the groupconsisting of a color change, a texture change, a smell change, and achemical release causing a change in a material physical characteristic.In one form of such embodiment, the failure ring includes microcapsulesin the molded end cap at the noted open axial end, which microcapsuleswhen ruptured produce one of the noted changes. In one desirableembodiment, the microcapsules rupture to provide a color change fromgreen to red, wherein green indicates good, and red indicates bad ordamaged. The fracture indicator may be potted into or adhered to theoutside of a urethane end cap. The indicator can be made of a very thinpouch with printing on the surface, and would contain a clear viewingwindow, which would show the green colored microbeads inside. When theaxial end of the filter element at the end cap is hit with an impactforce above a designated level, the microbeads would rupture or pop andbleed into the entire viewing area, revealing a red color. This wouldshow the customer that the pleat tip seals of the element may becomprised. The indicator label may have printed instructions telling acustomer: do not clean; and red panel means discard the element. Thelabel and indicator would also help customers identify that they areusing an original equipment manufacturer product and differentiate samefrom unauthorized replacement elements. In another example, the failurering may be provided by a pressure sensitive film containing themicrocapsules. For example, a pressure sensitive film produced by Fujiunder the trademark PRESSUREX is a Mylar based film that contains alayer of microcapsules. The application of force upon the film causesthe microcapsules to rupture, producing an instantaneous and permanenthigh resolution topographical image of pressure variation across thecontact area. The pressure indicating sensor film may be placed betweenany two surfaces that touch, mate or impact. Pressure can be applied andthe film then removed, whereupon the film reveals the pressuredistribution profile that occurred between the two surfaces. This isconceptually similar to litmus paper, with the color intensity of thenoted pressure indicating sensor film directly related to the amount ofpressure applied to it. The greater the pressure, the more intense thecolor.

In the above embodiments, the reinforcement ring is at the open firstaxial end 62 of the annular filter element. In a further embodiment, areinforcement ring 392, FIG. 32, may be provided at the noted secondaxial end 64. In further embodiments, two axially distally oppositereinforcement rings 302, 392 are provided, as shown in FIG. 32. One orboth of the rings 302, 392 may include or be replaced by a failure ring,which in one embodiment includes the noted microcapsules in a respectivemolded end cap 66, 76 at the respective axial end 62, 64, whichmicrocapsules when ruptured produce the noted change. The failure ringmay include an indication, such as shown at failure ring strip 394 inFIG. 33, such as “do not clean”, “red panel=discard element”, and so on.

The above embodiments show an annular filter element. In anotherembodiment, the filter element is a panel filter element such as shownat 396 in FIG. 34. The panel filter element includes filter media 398having a perimeter or border 400 which may include a frame and/or sealfor mounting in a housing. A reinforcement band 402 is provided along atleast a portion of the perimeter and performs the noted support functionthereat upon attempted percussive cleaning of filter element 396 byservice personnel striking perimeter 400 against an impact surface suchas 304, FIG. 15. Panel filter element 396 is generally flat and may havevarious perimeteral border shapes, including rectangular. The notedreinforcement band at 402 may include or be replaced by a failure band404 along at least a portion of perimeter 400 and performing the noteddesignated failure function to the noted failure condition thereat uponattempted percussive cleaning of filter element 396 by service personnelstriking perimeter 400 against an impact surface, e.g. at 304, thefailure condition providing at least one of: a) an indication to servicepersonnel that the filter element has been damaged and should not bere-installed; and b) a deformed condition preventing re-installation.Indicia may be provided on failure band 404, for example comparably toindicia band 394, FIG. 33.

In the foregoing description, certain terms have been used for brevity,clearness, and understanding. No unnecessary limitations are to beinferred therefrom beyond the requirement of the prior art because suchterms are used for descriptive purposes and are intended to be broadlyconstrued. The different configurations, systems, and method stepsdescribed herein may be used alone or in combination with otherconfigurations, systems and method steps. It is to be expected thatvarious equivalents, alternatives and modifications are possible withinthe scope of the appended claims.

1. A filter element for filtering fluid, comprising annular filter mediahaving an outer circumference, and an inner circumference defining ahollow interior, and extending axially between first and second axialends, said first axial end having an axially facing end face extendingradially between inner and outer circumferences, and an end cap at saidfirst axial end and extending axially away from said end face in a firstaxial direction, said second axial end being axially spaced from saidfirst axial end along a second axial direction, said first axialdirection being opposite to said second axial direction, an annularouter liner extending axially along said outer circumference andextending in said first axial direction beyond said end face and intosaid end cap and providing a percussion band performing a supportfunction upon attempted percussive cleaning of said filter element byservice personnel striking said first axial end at said outercircumference against an impact surface, wherein said outer linerextending into said end cap has a reinforcement segment turned away fromsaid outer circumference and radially inwardly toward said innercircumference and providing said percussion band, said reinforcementsegment has a turn-back portion turned back axially in said second axialdirection toward said end face, said turn-back portion has a terminationend axially spaced from said filter media by a section of said end capaxially interposed therebetween.